Cocaine Alters Learning and Memory in Brain

Cocaine, a highly purified extract taken from leaves of the Erythroxylum coca bush, a plant found in the Andes region of South America, is a dangerous drug that can lead to a growth in the brain size linked with learning and memory, according to a recent study.

Researchers have found that this could potentially explain the addictiveness of the drug.

According to researchers at the University of California San Francisco, they found that this growth is particularly evident in an animals' frontal cortex and may explain the density of dendritic spine increases.

The Frontal cortex in humans and other primates is the brain's largest lobe and comprises of a number of cytoarchitectonic areas. It's responsible for decision-making, higher reasoning and discipline, with newer dendritic spines--structures that require signaling in various regions.

The study looked at two sets of mice--one that received cocaine and the other that was given saline. Researchers used 2-photon laser scanning microscopes in order to look at each nerve cells within the brain of live mice.

Studies show that cocaine is a powerfully addictive drug that can harm the central nervous system when snorted, injected or smoked. Users at risk for heart attacks, including those suffering from respiratory failure, strokes, seizures, abdominal pain and nausea may experience sudden death upon using the drug, according to the National Institute of Frug Abuse (NIDA). Yet many scientists have been uncertain as to why the drug was so addictive.

"It's been observed that long-term drug users show decreased function in the frontal cortex in connection with mundane cues or tasks, and increased function in response to drug-related activity or information. This research suggests how the brains of drug users might shift toward those drug-related associations, "said Linda Wilbrecht, PhD, from UC Berkeley, lead author of the study. Wilbrecht worked on the study when she was at UCSF.

The first experiment gave one group of mice cocaine and the other group saline solution. Brain activities were observed two hours before and two hours after the cocaine injection.

The final experiment looked at mice given cocaine or saline for a week in separate chambers. Each chamber had its distinct design and texture just a week after researchers let the mice decide which chamber they wanted to go in.

Results showed that animals with the highest quantity of robust dendritic spines were the most likely to pick a chamber where they could receive cocaine.

More information regarding the findings can be found in the journal Nature Neuroscience.